Some patients with chronic brain lesions suffer from language deficits due to structural or functional disruption of language circuits, while others have normal language function. It has been postulated that the brains of those with preserved language (despite longstanding structural or focal electrical lesions due to frequent seizures in areas typically considered crucial for language) have undergone a shift of language processing indicative of cortical plasticity. Such reorganization in response to brain injury is believed to be dependent on identifiable factors including age at onset of pathology, presence/location of structural lesions, and gender. This proposal aims to identify the factors that allow for shifts of language-related cortex in response to chronic electrical and/or structural brain lesions. I will perform functional MRI (fMRI) studies to non-invasively examine cortical activation during three language tasks: i) single word repetition, ii) single word oral reading and iii) picture naming. The three subject groups investigated will include normal controls, patients with medically intractable seizures, and patients with cerebral arteriovenous malformations (AVMs). The lesion literature and functional imaging of normals will be used to delineate the normal range of cortex involved in each language function. The regions identified via fMRI of patients will then be compared to these task specific ranges of localization norms to determine which patients demonstrate reorganization of language cortex. The age at onset of pathology, the presence/site of any structural brain lesion, and gender of each patient will then be analyzed and conclusions drawn regarding the role that each of these factors plays in the brain?s ability to undergo reorganization of language-related cortex. Such information will be useful in guiding therapy for patients with both chronic and acute brain lesions, which potentially affect language-related areas.